$$(x-y)(x-10)+1=0$$
$y=-\frac{x^{2}-10x+1}{10-x}$
$x\neq 10$
$x=\frac{\sqrt{\left(y-12\right)\left(y-8\right)}+y+10}{2}$
$x=\frac{-\sqrt{\left(y-12\right)\left(y-8\right)}+y+10}{2}$
$x=\frac{\sqrt{\left(y-12\right)\left(y-8\right)}+y+10}{2}$
$x=\frac{-\sqrt{\left(y-12\right)\left(y-8\right)}+y+10}{2}\text{, }y\leq 8\text{ or }y\geq 12$